Vernier adjustment for a pinion stand and the like

ABSTRACT

A pair of rolls each having a peripheral groove in which there is an embossed half-thread. The rolls are on parallel shafts which are driven by a pinion stand. The pinion stand is provided with a device for making a vernier adjustment of the top roll&#39;&#39;s circumferential or rotational angle position with respect to the bottom roll so that the half-threads thereon will impress a smooth, continuous full thread on a rod passing between the rolls. One shaft is driven through the vernier device which comprises a coupling element in which there are two sets of internal gear teeth one of which is straight and the other of which is helical. The coupling element is rotated with a hollow gear which meshes with the straight internal teeth. A driven shaft extends out of the coupling element through the hollow gear and has a gear which engages with the internal helical teeth. Shifting the coupling element axially causes it to slide on the straight teeth and effect a torque on the helical teeth which changes the phase angle of the shaft of the top roll with respect to the shaft of the bottom roll and effects the desired rotational angle correction between the rolls.

United States Patent Chatterjee I Y 1 Aug. 29, 1972 [54] VERNIER ADJUSTMENT FOR A PINION STAND AND THE LIKE [72] Inventor: Ranjit K. Chatterjee, Reading, Pa. [73] Assignee: Birdsbono Corporation [22] Filed: April 15, 1971 [21] Appl. No.: 134,343

[52] US. Cl. ..72/198, 72/237, 74/89.14, 72/199 [51] Int. Cl. ..B2lh 3/04, 1321b 7/02, B2lb 31/16 [58] Field of Search ..72/196, 184, 243, 199, 249, 72/198, 240, 237; 74/89.14

[56] References Cited UNITED STATES PATENTS 3,469,460 9/ 1969 Mersch ..74/89.14 X 3,077,131 2/1963 McShane ..72/198 2,911,865 11/ 1959 Brickman 72/ 198 Primary ExaminerMilton S. Mehr Att0rneyWiviott & Hohenfeldt ABSTRACT A pair of rolls each having a peripheral groove in which there is an embossed half-thread. The rolls are on parallel shafts which are driven by a pinion stand. The pinion stand is provided with a device for making a vernier adjustment of the top rolls circumferential or rotational angle position with respect to the bottom roll so that the half-threads thereon will impress a smooth, continuous full thread on a rod passing between the rolls. One shaft is driven through the vernier device which comprises a coupling element in which there are two sets of internal gear teeth one of which is straight and the other of which is helical. The coupling element is rotated with a hollow gear which meshes with the straight internal teeth. A driven shaft extends out of the coupling element through the hollow gear and has a gear which engages with the internal helical teeth. Shifting the coupling element axially causes it to slide on the straight teeth and effect a torque on the helical teeth which changes the phase angle of the shaft of the top roll with respect to the shaft of the bottom roll and effects the desired rotational angle correction between the rolls.

7 Claims, 5 Drawing figures PATENIEDmszs 1912 saw 1 UF 5 INVENTOR RANJIT K CHATTERJEE WM? M ATTORNEYS N INVENTOR- RANJIT K. CHATTERJ EE PATENTEIJMI 1912 3.686318 SHEET 3 OF 3 INVENTOR RANJIT K CHATTERJEE ATTORNEYS VERNIER ADJUSTMENT FOR A PINION STAND AND THE LIKE BACKGROUND OF THE INVENTION The present invention may be used in connection with apparatus for rolling continuous threads on a plurality of hot metal rods. Such rods may be used, for example, as reinforcement in prestressed concrete castings. The rods can be cut to any length and still provide a threaded end that will accept a nut by which the rod may be anchored in the prestressed concrete form. Threaded reinforcing rod is formed by passing a hot rod between two 49 for each have a semi-circular peripheral groove in which a half-thread is embossed. When the rod is squeezed between the rolls and advanced by rotation thereof, a continuous thread is formed. It is important, however, for the rotational angle relationship between the rolls to be correct initially or be subject to adjustment during operation in order to assure that each of the half-threads will properly align to form a smooth continuous helix. The present invention permits vernier adjustment of one roll in either circumferential direction with respect to the other while the rolls are either standing or rotating.

The new vernier adjustment is used in a pinion stand which is well-known in the steel making art as it is commonly used for driving rolling mills and the like.

SUMMARY OF THE INVENTION An object of the present invention is to provide a device for making a vernier adjustment of the rotational position of one roll or shaft with respect to another without interrupting rotation of the shafts.

A more specific object of this invention is to provide a vernier adjustment which may be readily installed in a pinion stand and'a variety of other mechanical devices in which it may be desired to alter the rotational angle between two rotating shafts.

Another more specific object is to provide a vernier adjustment which converts a relatively small translational force into a torque that advances or retards one shaft circumferentially with respect to another.

An embodiment of the invention may be characterized concisely as comprising a driving shaft which is parallel with its coacting driven shaft. The driven shaft is surrounded by a hollow gear which is meshed with a gear that is on the driving shaft. The hollow gear has straight teeth at one end. These straight teeth engage with straight fear teeth which are internal to a rotating coupling element. The coupling element is joumaled for rotation on a support which may be shifted axially so that the coupling element slides with respect to the straight teeth. Also within the coupling element are some internal helical gear teeth which engage with a gear that is on the driven shaft and extends into the coupling element through the hollow gear. Thus, translation of the coupling element does not disturb the angular relationship between its internal straight teeth and the gear which drives it but it does cause rotation of the gear on the driven shaft by virtue of the helical gear exerting a torque thereon.

How the foregoing objects and other more specific objects are achieved will appear from time to time throughout the course of the ensuing description of an illustrative embodiment of the invention taken in conjunction with the drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of a pinion stand which incorporates the new vernier adjustment;

FIG. 2 is a fragmentary view of a part of the apparatus of FIG. 1 which is shown partly in section and enlarged;

FIG. 3 is a side view of a pair of grooved rolls for forming a continuous thread on a plurality of rods, the rolls being removed from their supporting structure;

FIG. 4 is a top view of the rolls shown in the preceding figure and showing threaded rod extending from between them on one side and unthreaded rod in the other; and

FIG. 5 is an end view of the thread-forming roll cooperating to impress a continuous thread on a rod.

DESCRIPTION OF A PREFERRED EMBODIMENT Refer to FIGS. 3-5 in connection with which use of the new vernier adjustment will be outlined. FIG. 3 shows a top roll 10 and a bottom roll 11 which are respectively on parallel shafts l2 and 13. The journals have been omitted since they are conventional. Each roll is provided with a series of peripheral grooves such as 14 and 15. The grooves are substantially semi-circular in cross section so that confronting grooves on opposite rolls encircle a round rod 17 which is fed between the rolls and advanced by their rotation during a rolling and thread-forming process. Grooves l4 and 15 have semi-threads or thread-forming dies embossed in them. As rod 17 is advanced and squeezed between rolls 10 and 11 the die threads, which are typically identified by numerals l8 and 19, impress a corresponding continuous full helical thread on the rod.

FIG. 4 shows a continuously threaded rod 17 emerging from between top roll 10 and its cooperating bottom roll 11. One may see that unthreaded rod 17 goes in between the rolls and emerges as continuously threaded rod 17 It will be evident from inspection of FIG. 5 that in order to form a continuous and smooth thread on rod 17 it is desirable to make at least one of the rolls such as top roll 10 circumferentially adjustable to a limited degree to assure that is has the proper rotational phasing with bottom roll 11. In other words, one roll should be circumferentially adjustable with respect to the other so that the thread-forming dies in each roll are properly aligned to form a continuous and smooth helical thread on the rod. The new vernier adjustment permits initiating, maintaining and correcting the rotational position of one roll with respect to the other without interrupting the rolling process.

Refer now to FIG. 1 which shows a pinion stand in which the new vernier adjustment is incorporated. Extending from the left are two shafts 21 and 22 which are parallel with each other. By means which are not shown, shaft 21 may be coupled with shaft 13 of bottom roll 11 so that these two elements rotate together. Shaft 22 may be coupled with shaft 12 of top roll 10 by means which are not shown since they are conventional. It will be shown that shaft 21 rotates at constant speed during the thread-rolling process and that shaft 22 is subject to angular or circumferential adjustment so as to properly coordinate the top 10 and bottom 11 thread-forming rolls.

Driving shaft 21 is journaled in a roller bearing 23 which is in turn supported in a frame member 24. Spaced away from the latter is another frame member 25 which has a similar roller bearing in the vicinity of 26 for that portion of shaft 21 which extends to a coupling 27. Coupling 27 is shown broken away but it should be understood that this coupling is connected with a motor-driven shaft which is not shown.

Part of the pinion stand frame in FIG. 1 is broken away to show that shaft 21 has a pinion gear 28 keyed onto it. Thus, pinion gear 28 turns with driving shaft 21. Pinion gear 28 engages with a hollow gear 29 which revolves around driven shaft 22. Both of these gears 28 and 29 may have axially straight teeth. Hollow gear 29 is continuous with a hollow shaft extension 30 that is surrounded by a roller bearing structure 31 which is in turn mounted in frame24. There are bearing sleeves such as 32 interposed between shaft 22 and the extension 30 of the hollow gear 29 so that the hollow gear may rotate freely on shaft 22 to which it is not engaged. Hollow gear 29 has an extension to the right which is not readily visible in FIG. 1 but which will be understood at this juncture to extend into the vemier adjustment device which is generally designated 35 in FIG. 1.

As outlined earlier, the vemier adjustment device is subject to axial shifting. This will be explained more fully later in connection with FIG. 2. For the present, however, it is sufficient to observe-that the vemier has a shaft 36 extending from the rear of it. This shaft is pinned in a socket 83 at the end of an arm 37 which extends from a sliding sleeve 38. Sleeve 38 is slidable on a shaft 39 which is fixed on spaced-apart brackets 40 and 41. Sleeve 38 has an upwardly extending triangularly shaped integral arm 42 which is connected by means of a pin 43 to a link 44. Link 44 is pinned at 45 to a shaft 46 which is driven translationally under the influence of a worm gear 47 and a motor, not shown, but which may be suitably mounted on the backside of the chassis 48 in which the elements just described are mounted. In any event, it should be evident that translation of shaft 46 and link 44 will result in corresponding translation of arm 42, sleeve 38 and depending arm 37. Such translation in either direction will cause non-rotating shaft 36 of vemier device 35 to shift or translate axially for reasons which will be described shortly hereinafter in connection with FIG. 2. Before diverting attention from FIG. 1, one may note that there is suitable mechanism 49 for driving the sliding sleeve 38 and there is an indicator scale 50 which exhibits the degree of angular difference between driving shaft 21 and driven shaft 22 to thereby facilitate correction of any angular difference between shafts.

In FIG. 2, a part of driving pinion gear 28 is shown meshed with driven hollow gear 29. The hollow gear is journaled in a roller bearing which is mounted in frame 25. Gear 29 has a diametrally reduced extension 56 which has an external thread 57 for receiving an internally threaded bearing retaining ring 58. This construction, of course, prohibits hollow gear 29 from shifting axially without interfering with its rotation. The bearing has a conventional cap and grease seal assembly 59 which is bolted onto frame 25.

There is a first gear 60 pressed on the end extension 56 of hollow gear 29. A key 61 engages the hub 62 of gear 60 with extension 56 of hollow shaft 29 so that gear 60 and hollow shaft 29 rotate together. The teeth of gear 60 are identified by the reference numeral 63, and, as can be seen, these teeth are relatively short in their axial dimension.

The teeth 63 of gear 60 engage with relatively longer straight gear teeth 64 which are internal to a hollow cylindrical coupling element 65. It should be evident that when hollow gear 29 is rotated, gear 60 will rotate with it and drive cylindrical coupling element 65 rotationally by reason of teeth 63 of the driving gear engaging with a set of longer internal gear teeth 64 in the coupling element 65. It should also be noted that coupling element 65 may be shifted in either axial direction while hollow gear 29 is rotating and driving the coupling element as will soon be explained.

Rotationally adjustable driven shaft 22 extends through hollow gear 29 and terminates within coupling element 65 beyond first gear 60. At its terminal end, shaft 22 has a gear 68 fastened to it by means of a key 69. Gear 68 is retained endwise on shaft 22 by means of a bolted keeper plate 70. Gear 68 has a radial enlargement on which there are peripheral helical gear teeth 71. These teeth are also relatively short in axial dimension and engage with a set of helical gear teeth 72 which are internal to and integral with coupling element 65. The helix angle of helical teeth 72 is about 15 'in a commercial embodiment. These helical teeth are long in comparison with the teeth 71 on gear 68 which again permits coupling element 65 to be shifted axially with respect to second gear 68 as was the case with respect to the first gear 60. When coupling element 65 is shifted in either axial direction, coaction between helical teeth 72 and teeth 71 results in a slight rotation of second gear 68 and shaft 22 relative to first gear 60 and its connected hollow gear 29 which does not rotate because it is constrained by the straight gear teeth.

Cylindrical coupling element 65 is enclosed at its left end by means of a cap 73 which is shouldered to receive a sealing ring 74. The right end of coupling element 65 has an end plate 76 that has a radially extending part 77 which is bolted on to the end of the coupling element 65. The end plate also has an integral axially extending ring 78 which is engaged at its end by a bolted retainer ring 79. The interior of ring 78 supports the outer race 80 of a roller bearing 81. The inner race of the roller bearing is pressed on a stub shaft 36 and secured on it with a bolted retainer plate 82. Thus, coupling element 65 is joumaled for rotation on stub shaft 36. As was explained earlier in connection with FIG. 1, stub shaft 36 is fixed in a cylindrical socket 83 of a downwardly depending arm 37 which is fastened to sleeve 38 and translates with it. The stub shaft 36 is secured against withdrawing from socket 83 by means of an end bolted keeper plate 84. For the sake of completing the description of the structure one may note that axially sliding sleeve 38 may have bellows such as 85, see FIG. 2, for precluding the entry of dirt between stationary shaft 39 and axially translatable sleeve 38.

It will be evident from the structure described in the preceding paragraph that coupling element 65 is journaled for rotation on stub shaft 36 and that the whole coupling element can be shifted or translated axially while it is rotating by shifting shaft 36 through the agency of sleeve 38. Because of the helical teeth 72, gear 68 will be angularly advanced or retarded and the same will be true of shaft 22 to which it is fastened and the top thread roll which it drives. Such angular shaft will be in reference to any selected point on bottom thread roll 11. Hence, if inspection reveals that the upper and lower halves of the semi-threads on the reinforcing rod are not properly matched with each other, it is a simple matter for the operator to effect axial translation of the coupling element 65 and thereby make a vernier adjustment of the rotational angle phasing between the thread rolls.

Now that an illustrative embodiment of the new vernier adjustment device has been described in considerable detail it will be evident to those skilled in the art that the same principles can be embodied in various modified structures. For example, the long helical teeth 72 and the long straight teeth 64 which are now both internal to the coupling element could be on the outside of a suitable cylinder and meshed respectively with cooperating gear teeth 71 and 63 which could be on external concentric gears rather than internally as shown. The essence of the invention is the use of a first gear which has straight teeth and engages a second gear which has longer or shorter teeth in conjunction with a second axially displaced gear that cooperates with a helical gear so that when the latter is shifted axially it will slide and turn while the first gear maintains its angular position.

Although a preferred embodiment of the invention has been described in considerable detail, such description is to be considered as illustrative rather than limiting for the invention may be variously embodied and is to be limited only by interpretation of the claims which follow.

I claim:

1. A vernier device for changing the rotational angle of one rotating element with respect to another comprising:

a. first and second coaxially rotatable axially displaced gear means,

b. a coupling element having an axis of rotation and an axially displaced pair of gear means around said axis, one of said pair of gear means being meshed with and cooperating with said first gear means as set and the other of said pair of gear means being meshed with and cooperating with said second gear means as a set,

c. the teeth on the first and second gear means being of different axial length than the teeth of their cooperating gear means to permit sliding axial movement between the gear means in a set,

d. one set of cooperating gear means including at least one gear means which has helical teeth and e. means adapted to change simultaneously the axial position of corresponding gear means with respect to their cooperating gear means, whereby the helical gear means will effect angular rotation of its cooperating gear means.

2. The invention set forth in claim 1 including:

a. a bidirectionally shiftable support,

b. said coupling element being journaled for rotation on said support and shiftable therewith to effect angular rotation of said helical gear set with respect to the other gear set. 3. The invention set forth in claim 1 wherein:

a. said coupling element has a substantially cylindrical bore and said pair of gear means are internal of said bore, one internal gear means having straight teeth that are parallel with the rotational axis of the coupling element and the other axially displaced intemal gear means having helical teeth,

. said first gear means having straight external teeth cooperating with the said straight internal teeth and said second gear means having external teeth cooperating with said internal helical teeth,

c. a bidirectionally shiftable support,

. said coupling element being journaled for rotation on said support and shiftable axially of the coupling element therewith to effect angular rotation of the external gear means which cooperates with said internal helical gear means and to effect no angular rotation between the straight toothed internal and external gear means.

4. A vernier device for synchronizing the rotational angle between interconnected rotating elements comprising:

a. a shiftable support means,

b. a coupling element journaled for rotation on said support means and shiftable bidirectionally thereby,

c. a straight toothed gear means and a helical toothed gear means axially displaced from each other internally of said coupling element,

d. a first shaft which has an externally toothed gear means fixed thereon and is coaxial with the coupling element, said last named gear means extending into said coupling element and being engaged with said internal helical gear means,

e. other gear means concentric with and rotatable around said first shaft, said last named gearmeans having external teeth at least a part of which engage with said straight internal gear teeth inside said coupling element, and

f. means adapted to rotate said other gear means and thereby drive said coupling element rotationally,

g. whereupon shifting said coupling element axially will cause said helical internal gear to turn said external gear on the first shaft through a limited angle with respect to said other gear means.

5. The inventionset forth in claim 4 including:

a. a second shaft parallel with the said first shaft and having a gear affixed thereon that engages with the gear means which is rotatable around said first shaft, and

b. means coupling said second shaft with a driving power source.

6. The invention set forth in claim 4 including:

a. a pinion stand having journaled parallel shafts operatively coupled with said first and second shafts, respectively,

b. a thread forming roll means on each pinion stand shaft, said roll means each having a peripheral annular groove which is substantially semi-circular in cross section and constitutes a half-thread die for impressing a continuous thread on rod passing between said rolls.

7. Apparatus for impressing a continuous thread on a rod comprising:

a. a stand having parallel shafts journaled therein,

b. a thread forming roll on each shaft, the peripheries of the respective rolls being adjacent each other and each having a circumferential half-thread forming groove for acting on a rod passing between the rolls,

. means for adjusting the angular position of one roll with respect to the other so as to correct the alignment of the half-threads formed on a rod, said last the hollow gear and slidable axially thereon,

5. an internal helical gear in said coupling element axially displaced from said straight toothed internal gear,

6. said driven shaft extending into said coupling element through said hollow concentric gear and said driven shaft having an external gear meshed with said helical internal gear, and

7. support means on which said coupling element is journaled for rotation, the support means being bidirectionally movable to shift the coupling element axially whereupon said helical gear will rotate its cooperating external gear through a limited angle to change its angular relation with respect to said straight toothed gear. 

1. A vernier device for changing the rotational angle of one rotating element with respect to another comprising: a. first and second coaxially rotatable axially displaced gear means, b. a coupling element having an axis of rotation and an axially displaced pair of gear means around said axis, one of said pair of gear means being meshed with and cooperating with said first gear means as a set and the other of said pair of gear means being meshed with and cooperating with said second gear means as a set, c. the teeth on the first and second gear means being of different axial length than the teeth of their cooperating gear means to permit sliding axial movement between the gear means in a set, d. one set of cooperating gear means including at least one gear means which has helical teeth and e. means adapted to change simultaneously the axial position of corresponding gear means with respect to their cooperating gear means, whereby the helical gear means will effect angular rotation of its cooperating gear means.
 2. The invention set forth in claim 1 including: a. a bidirectionally shiftable support, b. said coupling element being journaled for rotation on said support and shiftable therewith to effect angular rotation of said helical gear set with respect to the other gear set.
 2. a gear fastened on said drive shaft,
 3. a hollow gear concentric with and revolvable around said driven shaft and being meshed with the drive shaft gear, said hollow gear having axially straight teeth at one end,
 3. The invention set forth in claim 1 wherein: a. said coupling element has a substantially cylindrical bore and said pair of gear means are internal of said bore, one internal gear means having straight teeth that are parallel with the rotational axis of the coupling element and the other axially displaced internal gear means having helical teeth, b. said first gear means having straight external teeth cooperating with the said straight internal teeth and said second gear means having external teeth cooperating with said internal helical teeth, c. a bidirectionally shiftable support, d. said coupling element being journaled for rotation on said support and shiftable axially of the coupling element therewith to effect angular rotation of the external gear means which cooperates with said internal helical gear means and to effect no angular rotation between the straight toothed internal and external gear means.
 4. A vernier device for synchronizing the rotational angle between interconnected rotating elements comprising: a. a shiftable support means, b. a coupling element journaled for rotation on said support means and shiftable bidirectionally thereby, c. a straight toothed gear means and a helical toothed gear means axially displaced from each other internally of said coupling element, d. a first shaft which has an externally toothed gear means fixed thereon and is coaxial with the coupling element, said last named gear means extending into said coupling element and being engaged with said internal helical gear means, e. other gear means concentric with and rotatable around said first shaft, said last named gear means having external teeth at least a part of which engage with said straight internal gear teeth inside said coupLing element, and f. means adapted to rotate said other gear means and thereby drive said coupling element rotationally, g. whereupon shifting said coupling element axially will cause said helical internal gear to turn said external gear on the first shaft through a limited angle with respect to said other gear means.
 4. a rotatable coupling element having a straight toothed internal gear meshed with the teeth of the hollow gear and slidable axially thereon,
 5. The invention set forth in claim 4 including: a. a second shaft parallel with the said first shaft and having a gear affixed thereon that engages with the gear means which is rotatable around said first shaft, and b. means coupling said second shaft with a driving power source.
 5. an internal helical gear in said coupling element axially displaced from said straight toothed internal gear,
 6. The invention set forth in claim 4 including: a. a pinion stand having journaled parallel shafts operatively coupled with said first and second shafts, respectively, b. a thread forming roll means on each pinion stand shaft, said roll means each having a peripheral annular groove which is substantially semi-circular in cross section and constitutes a half-thread die for impressing a continuous thread on rod passing between said rolls.
 6. said driven shaft extending into said coupling element through said hollow concentric gear and said driven shaft having an external gear meshed with said helical internal gear, and
 7. support means on which said coupling element is journaled for rotation, the support means being bidirectionally movable to shift the coupling element axially whereupon said helical gear will rotate its cooperating external gear through a limited angle to change its angular relation with respect to said straight toothed gear.
 7. Apparatus for impressing a continuous thread on a rod comprising: a. a stand having parallel shafts journaled therein, b. a thread forming roll on each shaft, the peripheries of the respective rolls being adjacent each other and each having a circumferential half-thread forming groove for acting on a rod passing between the rolls, c. means for adjusting the angular position of one roll with respect to the other so as to correct the alignment of the half-threads formed on a rod, said last named means including: 